Effects of atrazine on fish, amphibians, and aquatic reptiles: a critical review.
The herbicide atrazine is widely used in agriculture for the production of corn and other crops. Because of its physical and chemical properties, atrazine is found in small concentrations in surface waters--habitats for some species. A number of reports on the effects of atrazine on aquatic vertebrates, mostly amphibians, have been published, yet there is inconsistency in the effects reported, and inconsistency between studies in different laboratories. We have brought the results and conclusions of all of the relevant laboratory and field studies together in this critical review and assessed causality using procedures for the identification of causative agents of disease and ecoepidemiology derived from Koch's postulates and the Bradford-Hill guidelines. Based on a weight of evidence analysis of all of the data, the central theory that environmentally relevant concentrations of atrazine affect reproduction and/or reproductive development in fish, amphibians, and reptiles is not supported by the vast majority of observations. The same conclusions also hold for the supporting theories such as induction of aromatase, the enzyme that converts testosterone to estradiol. For other responses, such as immune function, stress endocrinology, parasitism, or population-level effects, there are no indications of effects or there is such a paucity of good data that definitive conclusions cannot be made.
Solomon
Keith R
KR
Department of Environmental Biology and Centre for Toxicology, University of Guelph, Guelph, Ontario, Canada. ksolomon@uoguelph.ca
Carr
James A
JA
Du Preez
Louis H
LH
Giesy
John P
JP
Kendall
Ronald J
RJ
Smith
Ernest E
EE
Van Der Kraak
Glen J
GJ
D000663:Amphibians / Q000502:physiology*; D000818:Animals; D001280:Atrazine / Q000633:toxicity*; D001522:Behavior, Animal / Q000187:drug effects; D004703:Endocrine System / Q000187:drug effects; D004781:Environmental Exposure / Q000009:adverse effects*; D005399:Fishes / Q000502:physiology*; D006540:Herbicides / Q000633:toxicity*; D007107:Immune System / Q000187:drug effects; D024510:Muscle Development / Q000187:drug effects; D012098:Reproduction / Q000187:drug effects; D012104:Reptiles / Q000502:physiology*; D046468:Sexual Development / Q000187:drug effects; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D006540:Herbicides; D014874:Water Pollutants, Chemical; D001280:Atrazine